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Re: [PATCH 1/4] revision: make handle_dotdot() interface less confusing

From
Junio C Hamano <gitster@pobox.com>
Date
Mar 27, 2026, 15:55 UTC
Message-ID
<xmqqv7ehmfmh.fsf@gitster.g>
In-Reply-To
<20260326231415.GA420281@coredump.intra.peff.net>
Jeff King <peff@peff.net> writes:
Show 13 quoted lines
>> And once we accept that it is inevitable to make a copy, everything
>> else falls into the right place.
>
> Yeah, I don't think there is another good option. We can drop the
> "const" from the interface, which would be more honest, but then callers
> that use string literals have to either make their own copy, or cast
> away the constness and pray.
>
> The only "right" solution that avoids copying is if all of the
> lower-level functions learned to work with ptr/len pairs instead of
> NUL-terminated strings. But having done that sort of conversion before,
> it ends up quite messy and is prone to errors. Somebody is welcome to
> try tackling that if they want, but I don't. :)

We would need to call out to a library function or system call eventually down the callchain, at which point you'd need to somehow come up with a NUL-terminated equivalent of that <ptr, len> pair.

So I would avoid going down that path, unless the language itself has already abstracted that difference away, and C is not among those languages.

Previous: Jeff KingNext: Jeff King
Message 11 of 24 in “ISOC23: quell warnings on discarding const”
  1. 0/6 ISOC23: quell warnings on discarding constMichael J Gruber, Mar 26, 2026
  2. 5/6 do not discard const: keep signatureMichael J Gruber, Mar 26, 2026
  3. Junio C HamanoMar 26, 2026
  4. 6/6 do not discard const: the ugly truthMichael J Gruber, Mar 26, 2026
  5. Junio C HamanoMar 26, 2026
  6. Jeff KingMar 26, 2026
  7. 0/4 fix const issues in revision parserJeff King, Mar 26, 2026
  8. 1/4 revision: make handle_dotdot() interface less confusingJeff King, Mar 26, 2026
  9. Junio C HamanoMar 26, 2026
  10. Jeff KingMar 26, 2026
  11. Junio C HamanoMar 27, 2026
  12. 2/4 rev-parse: simplify dotdot parsingJeff King, Mar 26, 2026
  13. 3/4 revision: avoid writing to const string for parent marksJeff King, Mar 26, 2026
  14. 4/4 rev-parse: avoid writing to const string for parent marksJeff King, Mar 26, 2026
  15. 1/6 do not discard const: the simple casesMichael J Gruber, Mar 26, 2026
  16. Jeff KingMar 26, 2026
  17. Junio C HamanoMar 26, 2026
  18. config: store allocated string in non-const pointerJeff King, Mar 26, 2026
  19. 4/6 do not discard const: declare const where we stay constMichael J Gruber, Mar 26, 2026
  20. 2/6 do not discard const: make git-compat-util ISOC23-likeMichael J Gruber, Mar 26, 2026
  21. 3/6 do not discard const: adjust to non-const data typesMichael J Gruber, Mar 26, 2026
  22. Junio C HamanoMar 26, 2026
  23. D. Ben KnobleMar 26, 2026
  24. Michael J GruberMar 27, 2026

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